Pre-game history: Born in the Asgard region during the Ancient Kharlan War, Yuan was one of the first half-elves to be given a high military rank. Whether this was because of his capabilities or his lineage is unknown. However, this is what caught the interest of the Yggdrasill siblings, who were traveling around the world in hopes of ending discrimination. When they heard of a nefarious plot that Sylvarant had concocted, the two sought out the help of Kratos Aurion, a member of the Tethe’alla knighthood and one of Yuan’s opposers on the battlefield. Sadly, despite their meeting with Tethe’alla’s king, Sylvarant’s plans could not be avoided and the capital was destroyed. Though the reason or method are never mentioned, Kratos introduced the two siblings to Yuan. The Sylvarantian half-elf was determined to prove that the dream the Yggdrasills shared was nothing but hypocrisy and decided to travel with them. Kratos Aurion, who had been relieved of his knightly duties, took Mithos on as his student and journeyed with them as well. This is how the ‘Four Kharlan Heroes’ were born.

Together, the four heroes went on a whole bunch of crazy adventures. Niflheim, Ozette flues, Centurions, Chronic Angelus Crystallus Inofficium… They saw it all. Because, yes, apparently quite early in their journey they acquired Cruxis Crystals and reached the status of Seraph. Meanwhile, the war raged on and eventually, thanks to overuse of magi-technology, the great tree which provided Mana for the world withered away. After what must have been a tiring journey, Mithos had made pacts with all the Summon Spirits and used their powers to aid their ideals. Mithos gained control of the Eternal Sword, a weapon forged especially for him by the king of Summon Spirits; Origin. With this, the lands of Sylvarant and Tethe’alla were split apart, becoming two different worlds on shifted dimensions. The Great Tree’s seed was placed in the center of the worlds, protected by so-called Mana Links, and the hourglass system was created as a temporary measure to preserve both worlds. The four heroes had planned to resurrect the tree later, using the blessing of Derris-Kharlan. This was a comet consisting of Mana, which passed the planet Aselia every hundred years.

Sadly, everything went wrong when Martel was assassinated by a human who was trying to take control of the Mana. Unable to accept his sister’s death, Mithos tied her Cruxis Crystal, which contained her conscience, to the Great Seed. Derris-Kharlan, which appeared not long after, was bound to the planet by the Eternal Sword, its Mana being fed to the seed to keep Martel’s soul alive. Soon after, the organization of Cruxis was created, with Mithos at its head. Believing in the boy’s ideals, both Yuan and Kratos became his right-hand men. Though Kratos pledged his loyalty to Mithos completely, Yuan had his doubts about what they were doing. He knew that Martel’s final wish wasn’t meant to be interpreted in such a way, neither would she want to be revived at the cost of anyone else’s life. Neither Kratos, nor Mithos would listen to his words. Therefore, he took matters into his own hands and started his own, underground organization; the Renegades. Having to remain in the shadows to maintain his cover as double-agent, Yuan hardly ever took care of business himself. All field missions were left in the hands of his capable lieutenant as he pretended to be loyal to Cruxis, meanwhile leaking all sorts of information to his subordinates. He also manipulated Rodyle, one of the Grand Cardinals, into building a Mana Cannon, with which he would destroy the Tower of Salvation. At several points in time, Yuan cautiously approached Kratos, asking him to release Origin’s seal. Sadly, all his attempts were cut short. Later, Kratos realized on his own that Mithos’ ideal of an Age of Lifeless Beings wasn’t the proper ideal to cling to, and began to search for a way for humans to wield the Eternal Sword. This is how the man met Anna. A few years later, after his wife and son were seemingly killed, Yuan approached him once more. The only response he received was that Kratos simply “did not care anymore”.

A Luceti resident since mid-January 2008, Yuan has now adapted to his strange new living situation. Well, as far as you can call it adapting. The idea of experiments, no more decent magic and small feathery wings still aggravates him deeply. By now, he's been taken by the Malnosso for experiments twice. He's living with Zoisite (Sailor Moon series), finally realizing there's no point in clinging to Martel's memory. He's lost two of those already since his arrival, and is now being 'taunted' by the end-game Summon Spirit version. As he lost his engagement ring (again!) at one point, it fell into Mithos' hands. After a great deal of teasing, Mithos eventually tossed it into the river and it was never recovered. The Malnosso returned it to him as a Christmas present in December 2008.

He can generally get along with most of the old ToS cast, but prefers not to. He's not oblivious to the way some of them think about him, after all. Over time, Yuan made a few 'friends', such as Usagi Tsukino and Albert Silverberg. He believes that the only way to save Luceti from the Malnosso is to create some order in this chaotic little village. He's not about to take charge himself, though, because he knows he'll be ignored. Therefore, he's hoping the 'council' gatherings will benefit the residents. Helping Albert and co keep things organized during the more chaotic events, such as the opening of a mysterious tunnel, is really all he's good for. Yuan has a tendency to retreat into the forest when things get too hard for him to handle in the village.

He died once, during the epidemic experiment. The cost of his revival was his ability to see colors. It's not quite the same as being colorblind, but similar in a way, seeing as his entire world is black and white now. He'd been turned into a cat for a week or so because of the animal experiment and has also experienced womanhood by now. During the age experiment, Yuan spent a great deal of time hanging out with Raine, up to the point where he was almost adopted into the Sage family. When Sophie Coolidge was born and the pixies blessed most of the residents with plushies, Yuan received a cow. He was not amused. During The Haunted he was visited by the spirits of Martel and Yggdrasill, but paid little attention to them. He was preoccupied with other matters, at the time. When Zelman lost control and starting turning people into vampires (also known as Kowloon kids), Yuan was one of the victims. However, Kratos subdued him before he caused too much damage. After Tenebrae and other Dawn of the New World characters appeared in the village, he was informed of his future to some degree. As such, he's come to accept his task as Guardian of the New World Tree. During the Valentine's Day experiment in 2009, he fell for one of the new arrivals; Zoisite. Even after the event had passed, he still allowed the man to stay in his house, working on finally moving on from Martel.